A dump truck includes a body for loading soil, stone or the like and a frame on which the body is mounted. Usually, a rear part of the body is pivotably supported at a rear end of the frame and a front part of the body is hoistably supported by the frame by means of a hoist cylinder. With this configuration, in the case of the dump truck, an up operation or down operation of an operating lever by the operator of the dump truck causes the hoist cylinder to extend or retract, which makes it possible to control hoisting of the body, with the rear part of the body serving as a fulcrum point. Conventionally, a dump truck is known, which schematically displays a motion picture of a hoisting state of the body during the body is under hoisting control (cf., for example, Patent Document 1)